The vascular endothelium is important in maintaining hemostasis and vascular tone. Because of its unique location, it is readily exposed to circulating mediators, many of which influence fundamental cellular processes. Tumor necrosis factor is one of the inflammatory mediators that critically affects endothelial cell function. This proposal, entitled Prostaglandin Regulation in Vascular Endothelium, will explore an important aspect of endothelial cell physiology disrupted by tumor necrosis factor: the regulation of prostaglandin synthesis. This project will specifically examine the mechanism whereby tumor necrosis factor increases prostaglandin metabolism in endothelial cells. Tumor necrosis factor and prostaglandins play a role in a number of human conditions.